HAVANA, May 19 (Reuters) - Flags flew at half-mast in Cuba on Saturday marking the start of two days of national mourning while authorities worked to identify the corpses of more than 100 people who died in the crash of a Boeing 737 shortly after takeoff from Havana.
Distressed relatives of victims of Friday's crash, most of whom are Cuban, cried and hugged one another outside the morgue, where they gave information on their loved ones to authorities to help the process of identification.
Three women survived the crash, the worst in Cuba in nearly 30 years, but they were in a critical condition, suffering burns and other trauma, the director of the hospital in Havana where they were being treated said on Saturday.
The nearly 40-year old plane had been carrying 105 passengers plus crew members on a midday domestic flight to Holguin in eastern Cuba, Cuban state-run media said. Two Argentine citizens and an unspecified number of Mexicans were among the dead, the Argentine and Mexican governments said.
Cuban investigators were working around the clock at the site of the crash, an agricultural area some 20 km (12 miles) south of Havana, sifting through the burned wreckage for evidence, Cuban officials said.
"This is a very unexpected death, she didn't deserve it, my grandmother was a strong person," said Cuban 18-year old student Katherine Lucia Martinez, bursting into tears and clinging to her father.
Her 60-year old grandmother was among the dead, and she was waiting with other relatives of the deceased at a Havana hotel for an update from the authorities.
President Miguel Diaz-Canel on Saturday visited the morgue where the victims are being identified. The crash is the first big test of his presidency after taking over office from Raul Castro just last month.
On Friday he also visited the site of the crash.
Cuban specialists have recovered one of the plane's black boxes in "good conditions," the transport minister Adel Yzquierdo told Cuban state TV on Saturday.
Some locals said they saw the plane on fire before it hit the ground.
"The plane was on fire, it flipped and then nosedived," said Marino Perez Alvaredo, a farmer.
The Mexican transport department said on its website, "During take-off (the plane) apparently suffered a problem and dived to the ground."
The Boeing 737-201 aircraft was built in 1979 and leased by Cuban airline Cubana from a small Mexican company called Damojh, according to the Mexican government.
Damojh in Mexico said it did not immediately have any more information. Cubana declined to comment.
Mexico said it would send a team of investigators from its Directorate General of Civil Aeronautics on Saturday. Most aircraft accidents take months to investigate.
The crash was the worst since a Soviet-made Ilyushin-62M passenger plane crashed near Havana in 1989 killing all 126 people on board. (Reporting by Sarah Marsh Editing by Chris Reese)